Alkali-activation of CaO-FeOx-SiO2 slag: Formation mechanism from in-situ X-ray total scattering
Alkali-activation of CaO-FeOx-SiO2 slag: Formation mechanism from in-situ X-ray total scattering
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DOI：
10.1016/j.cemconres.2019.04.019
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发表时间：
2019-08-01
影响因子：
11.4
通讯作者：
Pontikes, Y.
中科院分区：
文献类型：
--
作者：
Peys, A.;White, C. E.;Pontikes, Y.
对低二氧化碳技术的追求导致了替代胶凝材料研究的激增，碱活化材料是其中的一个大家族。近年来，除了更常用的铝硅酸盐前体之外，碱激活材料已扩展到包括富铁前体。通过采用原位 X 射线全散射和随后的对分布函数分析，评估了两种富铁合成渣碱激活材料的形成机制。局部原子-原子关联的演变揭示了三个反应阶段。 Fe-硅酸盐簇从炉渣中溶解后，形成具有 Fe2+ 和 Fe3+ 氧化态 Fe 的粘结相。 Fe2+ 态以三八面体层的形式存在，与 Fe(OH)(2) 中的类似，而 Fe3+ 可能位于聚合硅酸盐网络中。暴露于空气中会导致 Fe2+ 物质转变为 Fe3+ 状态。
The pursuit of low-CO2 technologies has led to a surge in research on alternative cementitious materials, of which alkali-activated materials are a large family. In recent years alkali-activated materials have expanded to encompass Fe-rich precursors in addition to the more commonly employed aluminosilicate precursors. The formation mechanism of alkali-activated materials from two Fe-rich synthetic slags has been assessed by employing in-situ X-ray total scattering and subsequent pair distribution function analysis. The evolution of the local atom-atom correlations reveals three reaction stages. After the dissolution of Fe-silicate clusters from the slag, a binder phase is formed with Fe in both Fe2+ and Fe3+ oxidation states. The Fe2+ state is present in the form of trioctahedral layers, similar to those in Fe(OH)(2), while the Fe3+ is likely located in the polymerized silicate network. Exposure to air causes the Fe2+ species to transition to the Fe3+ state.